Develop Reference

Permanently Populate ListView With images?

I'm currently developing an app where I have a listview. This listview is populated with text and images fetched from a XML file online. It's populating correctly however, whenever you scroll, anything that wasn't currently on the screen reloads and recalculates the size of the bitmap to go in the listview. This leads to the scrolling being less fluid and annoying. How can I get my activity to populate the listview with the images and load them one time to stay there?
ImageLoader:
public class ImageLoader {
MemoryCache memoryCache = new MemoryCache();
FileCache fileCache;
private Map<ImageView, String> imageViews = Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
ExecutorService executorService;
int size;
int placeholderpic;
public ImageLoader(Context context, int size, int placeholderpic) {
fileCache = new FileCache(context);
executorService = Executors.newFixedThreadPool(5);
this.size = size;
this.placeholderpic = placeholderpic;
}
public void displayImage(String url, ImageView imageView) {
imageViews.put(imageView, url);
Bitmap bitmap = memoryCache.get(url);
if(bitmap != null)
imageView.setImageBitmap(bitmap);
else {
queuePhoto(url, imageView);
imageView.setImageResource(placeholderpic);
}
}
private void queuePhoto(String url, ImageView imageView) {
PhotoToLoad p = new PhotoToLoad(url, imageView);
executorService.submit(new PhotosLoader(p));
}
private Bitmap getBitmap(String url) {
File f = fileCache.getFile(url);
//from SD cache
Bitmap b = decodeFile(f);
if(b != null)
return b;
//from web
try {
Bitmap bitmap = null;
URL imageUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection)imageUrl.openConnection();
conn.setConnectTimeout(30000);
conn.setReadTimeout(30000);
conn.setInstanceFollowRedirects(true);
InputStream is=conn.getInputStream();
OutputStream os = new FileOutputStream(f);
Utils.CopyStream(is, os);
os.close();
bitmap = decodeFile(f);
return bitmap;
} catch (Throwable ex) {
ex.printStackTrace();
if(ex instanceof OutOfMemoryError)
memoryCache.clear();
return null;
}
}
//decodes image and scales it to reduce memory consumption
private Bitmap decodeFile(File f) {
try {
//decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeStream(new FileInputStream(f),null,o);
//Find the correct scale value. It should be the power of 2.
final int REQUIRED_SIZE = size;
int width_tmp = o.outWidth, height_tmp=o.outHeight;
int scale = 1;
while(true){
if(width_tmp/2 < REQUIRED_SIZE || height_tmp/2 < REQUIRED_SIZE)
break;
width_tmp /= 2;
height_tmp /= 2;
scale *= 2;
}
//decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
} catch (FileNotFoundException e) {}
return null;
}
//Task for the queue
private class PhotoToLoad {
public String url;
public ImageView imageView;
public PhotoToLoad(String u, ImageView i) {
url = u;
imageView = i;
}
}
class PhotosLoader implements Runnable {
PhotoToLoad photoToLoad;
PhotosLoader(PhotoToLoad photoToLoad){
this.photoToLoad = photoToLoad;
}
#Override
public void run() {
if(imageViewReused(photoToLoad))
return;
Bitmap bmp = getBitmap(photoToLoad.url);
memoryCache.put(photoToLoad.url, bmp);
if(imageViewReused(photoToLoad))
return;
BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad);
Activity a = (Activity)photoToLoad.imageView.getContext();
a.runOnUiThread(bd);
}
}
boolean imageViewReused(PhotoToLoad photoToLoad) {
String tag=imageViews.get(photoToLoad.imageView);
if(tag == null || !tag.equals(photoToLoad.url))
return true;
return false;
}
//Used to display bitmap in the UI thread
class BitmapDisplayer implements Runnable {
Bitmap bitmap;
PhotoToLoad photoToLoad;
public BitmapDisplayer(Bitmap b, PhotoToLoad p){
bitmap = b; photoToLoad = p;
}
public void run() {
if(imageViewReused(photoToLoad))
return;
if(bitmap != null)
photoToLoad.imageView.setImageBitmap(bitmap);
else
photoToLoad.imageView.setImageResource(placeholderpic);
}
}
public void clearCache() {
memoryCache.clear();
fileCache.clear();
}
ListView Adapter:
public class LazyNewsAdapter extends BaseAdapter {
private Activity activity;
private ArrayList<News> listData;
private LayoutInflater inflater = null;
public LazyNewsAdapter(Activity activity, ArrayList<News> listData) {
this.activity = activity;
this.listData = listData;
inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public int getCount() {
return listData.size();
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
News newsItem = listData.get(position);
View view = convertView;
if(convertView == null)
view = inflater.inflate(R.layout.news_cell, null);
TextView newsTitle = (TextView) view.findViewById(R.id.newsTitle);
TextView newsDate = (TextView) view.findViewById(R.id.newsDate);
ImageView image = (ImageView) view.findViewById(R.id.newsImage);
newsTitle.setText(newsItem.getNewsTitle());
newsDate.setText(newsItem.getNewsDate());
String url = newsItem.getNewsImageUrl();
ImageLoader imageLoader = new ImageLoader(activity, 600, R.drawable.placeholder);
imageLoader.displayImage(url, image);
return view;
}

You must use cache for that kind of things.
See Universal Image loader to load your images in an efficient way.
You must have only one instance of your imageLoader in an activity, dont instantiate it in each getView:
Do that line in your onCreate instead of getView:
ImageLoader imageLoader = new ImageLoader(activity, 600, R.drawable.placeholder);

Try to save online data to Array List variable. Then load it to list view with using notifydatasetChange

Use the listview optimization for the setting image in ListAdapter here's video tutorial that might help you also be sure to use Glide for setting the image as they take a step forward of recycling your Bitmap
https://www.youtube.com/watch?v=mKGoKnhN_Ys&index=91&list=PL1q3ROAofjeOUwh7lPBnGbg__DUodwLN7

my imageloder not change in imageview image if new image same name

below is my imageloader code which work fine if new image are diffrent name but if new image are same name then is not change images show old image only suppose i have image name myimage is display perfectly if i add new image in url with same name and delete previous my code again show previous image not show new image due to cache what is problem in this code help me please
private ImageLoader imgLoader;
private String strUrl = "http://solutionboat.com/work_2/asset/images/rifat.jpg";
private String strUrl1 = "http://solutionboat.com/work_2/asset/images/sobin.jpg";
private String strUrl2 = "http://solutionboat.com/work_2/asset/images/samol.jpg";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ImageView target0 = (ImageView) findViewById(R.id.target0);
ImageView target1 = (ImageView) findViewById(R.id.target1);
ImageView target2 = (ImageView) findViewById(R.id.target2);
imgLoader = new ImageLoader(this);
imgLoader.displayImage(strUrl, target0);
imgLoader.displayImage(strUrl1, target1);
imgLoader.displayImage(strUrl2, target2);
ViewFlipper flipper = (ViewFlipper) findViewById(R.id.viewFlipper1);
flipper.startFlipping();
}
}
ImageLoader class
public class ImageLoader {
MemoryCache memoryCache = new MemoryCache();
FileCache fileCache;
private Map<ImageView, String> imageViews =
Collections.synchronizedMap(new WeakHashMap<ImageView, String>());
ExecutorService executorService;
public ImageLoader(Context context) {
fileCache = new FileCache(context);
executorService = Executors.newFixedThreadPool(5);
}
final int stub_id = R.mipmap.ic_launcher;
public void displayImage(String url, ImageView imageView) {
imageViews.put(imageView, url);
Bitmap bitmap = memoryCache.get(url);
if(bitmap != null) {
imageView.setImageBitmap(bitmap);
} else {
queuePhoto(url, imageView);
imageView.setImageResource(stub_id);
}
}
private void queuePhoto(String url, ImageView imageView) {
PhotoToLoad p = new PhotoToLoad(url, imageView);
executorService.submit(new PhotosLoader(p));
}
private Bitmap getBitmap(String url) {
File f = fileCache.getFile(url);
Bitmap b = decodeFile(f);
if(b != null)
return b;
try {
Bitmap bitmap = null;
URL imageUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection) imageUrl.openConnection();
conn.setConnectTimeout(30000);
conn.setReadTimeout(30000);
conn.setInstanceFollowRedirects(true);
InputStream is = conn.getInputStream();
OutputStream os = new FileOutputStream(f);
Utils.copyStream(is, os);
os.close();
bitmap = decodeFile(f);
return bitmap;
} catch (Throwable ex) {
ex.printStackTrace();
return null;
}
}
private Bitmap decodeFile(File f) {
try {
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeStream(new FileInputStream(f), null, o);
final int REQUIRED_SIZE = 70;
int width_tmp = o.outWidth, height_tmp = o.outHeight;
int scale = 1;
while(true) {
if(width_tmp / 2 < REQUIRED_SIZE || height_tmp / 2 < REQUIRED_SIZE) {
break;
}
width_tmp /= 2;
height_tmp /= 2;
scale *= 2;
}
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
return null;
}
private class PhotoToLoad{
public String url;
public ImageView imageView;
public PhotoToLoad(String u, ImageView i) {
url = u;
imageView = i;
}
}
class PhotosLoader implements Runnable {
PhotoToLoad photoToLoad;
PhotosLoader(PhotoToLoad photoToLoad) {
this.photoToLoad = photoToLoad;
}
#Override
public void run() {
if(imageViewReused(photoToLoad)) {
return;
}
Bitmap bmp = getBitmap(photoToLoad.url);
memoryCache.put(photoToLoad.url, bmp);
if(imageViewReused(photoToLoad)) {
return;
}
BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad);
Activity a = (Activity) photoToLoad.imageView.getContext();
a.runOnUiThread(bd);
}
}
boolean imageViewReused(PhotoToLoad photoToLoad) {
String tag = imageViews.get(photoToLoad.imageView);
if(tag == null || !tag.equals(photoToLoad.url)) {
return true;
}
return false;
}
class BitmapDisplayer implements Runnable {
Bitmap bitmap;
PhotoToLoad photoToLoad;
public BitmapDisplayer(Bitmap b, PhotoToLoad p) {
bitmap = b;
photoToLoad = p;
}
#Override
public void run() {
if(imageViewReused(photoToLoad))
return;
if(bitmap != null){
photoToLoad.imageView.setImageBitmap(bitmap);
} else {
photoToLoad.imageView.setImageResource(stub_id);
}
}
}
public void clearCahce() {
memoryCache.clear();
fileCache.clear();
}
}

Use Picasso for any image loading/caching problems.
http://square.github.io/picasso/

Download image from URL - Android Parsing JSON

The problem is that when I open my activity shows the progress bar which while loop continuously and shows the following error code below.
There is a class project if you need more code ask in a comment
public class ImageLoader {
MemoryCache memoryCache = new MemoryCache();
FileCache fileCache;
private Map<ImageView, String> imageViews = Collections
.synchronizedMap(new WeakHashMap<ImageView, String>());
ExecutorService executorService;
// Handler to display images in UI thread
Handler handler = new Handler();
public ImageLoader(Context context) {
fileCache = new FileCache(context);
executorService = Executors.newFixedThreadPool(5);
}
final int stub_id = R.drawable.temp_img;
public void DisplayImage(String url, ImageView imageView) {
imageViews.put(imageView, url);
Bitmap bitmap = memoryCache.get(url);
if (bitmap != null)
imageView.setImageBitmap(bitmap);
else {
queuePhoto(url, imageView);
imageView.setImageResource(stub_id);
}
}
private void queuePhoto(String url, ImageView imageView) {
PhotoToLoad p = new PhotoToLoad(url, imageView);
executorService.submit(new PhotosLoader(p));
}
private Bitmap getBitmap(String url) {
File f = fileCache.getFile(url);
Bitmap b = decodeFile(f);
if (b != null)
return b;
// Download Images from the Internet
try {
Bitmap bitmap = null;
URL imageUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection) imageUrl
.openConnection();
conn.setConnectTimeout(30000);
conn.setReadTimeout(30000);
conn.setInstanceFollowRedirects(true);
InputStream is = conn.getInputStream();
OutputStream os = new FileOutputStream(f);
Utils.CopyStream(is, os);
os.close();
conn.disconnect();
bitmap = decodeFile(f);
return bitmap;
} catch (Throwable ex) {
ex.printStackTrace();
if (ex instanceof OutOfMemoryError)
memoryCache.clear();
return null;
}
}
// Decodes image and scales it to reduce memory consumption
private Bitmap decodeFile(File f) {
try {
// Decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
FileInputStream stream1 = new FileInputStream(f);
BitmapFactory.decodeStream(stream1, null, o);
stream1.close();
// Find the correct scale value. It should be the power of 2.
// Recommended Size 512
final int REQUIRED_SIZE = 70;
int width_tmp = o.outWidth, height_tmp = o.outHeight;
int scale = 1;
while (true) {
if (width_tmp / 2 < REQUIRED_SIZE
|| height_tmp / 2 < REQUIRED_SIZE)
break;
width_tmp /= 2;
height_tmp /= 2;
scale *= 2;
}
// Decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
FileInputStream stream2 = new FileInputStream(f);
Bitmap bitmap = BitmapFactory.decodeStream(stream2, null, o2);
stream2.close();
return bitmap;
} catch (FileNotFoundException e) {
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
// Task for the queue
private class PhotoToLoad {
public String url;
public ImageView imageView;
public PhotoToLoad(String u, ImageView i) {
url = u;
imageView = i;
}
}
class PhotosLoader implements Runnable {
PhotoToLoad photoToLoad;
PhotosLoader(PhotoToLoad photoToLoad) {
this.photoToLoad = photoToLoad;
}
#Override
public void run() {
try {
if (imageViewReused(photoToLoad))
return;
Bitmap bmp = getBitmap(photoToLoad.url);
memoryCache.put(photoToLoad.url, bmp);
if (imageViewReused(photoToLoad))
return;
BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad);
handler.post(bd);
} catch (Throwable th) {
th.printStackTrace();
}
}
}
boolean imageViewReused(PhotoToLoad photoToLoad) {
String tag = imageViews.get(photoToLoad.imageView);
if (tag == null || !tag.equals(photoToLoad.url))
return true;
return false;
}
// Used to display bitmap in the UI thread
class BitmapDisplayer implements Runnable {
Bitmap bitmap;
PhotoToLoad photoToLoad;
public BitmapDisplayer(Bitmap b, PhotoToLoad p) {
bitmap = b;
photoToLoad = p;
}
public void run() {
if (imageViewReused(photoToLoad))
return;
if (bitmap != null)
photoToLoad.imageView.setImageBitmap(bitmap);
else
photoToLoad.imageView.setImageResource(stub_id);
}
}
public void clearCache() {
memoryCache.clear();
fileCache.clear();
}
}
07-11 16:33:04.248: W/System.err(2234): java.net.MalformedURLException: Protocol not found: null
07-11 16:33:04.248: W/System.err(2234): at java.net.URL.<init>(URL.java:178)
07-11 16:33:04.248: W/System.err(2234): at java.net.URL.<init>(URL.java:127)
07-11 16:33:04.248: W/System.err(2234): at com.rozajacapp.ImageLoader.getBitmap(ImageLoader.java:66)
07-11 16:33:04.248: W/System.err(2234): at com.rozajacapp.ImageLoader.access$0(ImageLoader.java:56)
07-11 16:33:04.248: W/System.err(2234): at com.rozajacapp.ImageLoader$PhotosLoader.run(ImageLoader.java:148)
07-11 16:33:04.248: W/System.err(2234): at ava.util.concurrent.Executors$RunnableAdapter.call(Executors.java:442)
07-11 16:33:04.248:

I recommend you to use Google Volley librairy for HTTP request.
See the doc here : http://developer.android.com/training/volley/index.html
Some code for downloading Image :
ImageRequest ir = new ImageRequest(url, new Response.Listener<Bitmap>() {
#Override
public void onResponse(Bitmap response) {
iv.setImageBitmap(response);
}
}, 0, 0, null, null);
RequestQueue rq = Volley.newRequestQueue(this);
rq.add(ir);

ListView scrolling lag in android

I have a customized list view in my application, which is showing an image and text (Json). The image I am getting from URL is working, but listview is laggy (scrolling lag).
Maybe my problem is ImageLoader.java class
This is my code:
public class ImageLoader {
MemoryCache memoryCache = new MemoryCache();
FileCache fileCache;
private Map<ImageView, String> imageViews = Collections
.synchronizedMap(new WeakHashMap<ImageView, String>());
ExecutorService executorService;
public ImageLoader(Context context) {
fileCache = new FileCache(context);
executorService = Executors.newFixedThreadPool(5);
}
final int stub_id = R.drawable.aaaaaaaaaaaaaaa;
public void DisplayImage(String url, ImageView imageView) {
imageViews.put(imageView, url);
Bitmap bitmap = memoryCache.get(url);
if (bitmap != null)
imageView.setImageBitmap(bitmap);
else {
queuePhoto(url, imageView);
imageView.setImageResource(stub_id);
}
}
private void queuePhoto(String url, ImageView imageView) {
PhotoToLoad p = new PhotoToLoad(url, imageView);
executorService.submit(new PhotosLoader(p));
}
private Bitmap getBitmap(String url) {
File f = fileCache.getFile(url);
// from SD cache
Bitmap b = decodeFile(f);
if (b != null)
return b;
// from web
try {
Bitmap bitmap = null;
URL imageUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection) imageUrl
.openConnection();
conn.setConnectTimeout(30000);
conn.setReadTimeout(30000);
conn.setInstanceFollowRedirects(true);
InputStream is = conn.getInputStream();
OutputStream os = new FileOutputStream(f);
Utils.CopyStream(is, os);
os.close();
bitmap = decodeFile(f);
return bitmap;
} catch (Throwable ex) {
ex.printStackTrace();
if (ex instanceof OutOfMemoryError)
memoryCache.clear();
return null;
}
}
// decodes image and scales it to reduce memory consumption
private Bitmap decodeFile(File f) {
try {
// decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
FileInputStream stream1 = new FileInputStream(f);
BitmapFactory.decodeStream(stream1, null, o);
stream1.close();
// Find the correct scale value. It should be the power of 2.
final int REQUIRED_SIZE = 70;
int width_tmp = o.outWidth, height_tmp = o.outHeight;
int scale = 1;
while (true) {
if (width_tmp / 2 < REQUIRED_SIZE
|| height_tmp / 2 < REQUIRED_SIZE)
break;
width_tmp /= 2;
height_tmp /= 2;
scale *= 2;
}
// decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
FileInputStream stream2 = new FileInputStream(f);
Bitmap bitmap = BitmapFactory.decodeStream(stream2, null, o2);
stream2.close();
return bitmap;
} catch (FileNotFoundException e) {
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
// Task for the queue
private class PhotoToLoad {
public String url;
public ImageView imageView;
public PhotoToLoad(String u, ImageView i) {
url = u;
imageView = i;
}
}
class PhotosLoader implements Runnable {
PhotoToLoad photoToLoad;
PhotosLoader(PhotoToLoad photoToLoad) {
this.photoToLoad = photoToLoad;
}
#Override
public void run() {
try {
if (imageViewReused(photoToLoad))
return;
Bitmap bmp = getBitmap(photoToLoad.url);
memoryCache.put(photoToLoad.url, bmp);
if (imageViewReused(photoToLoad))
return;
BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad);
Activity a = (Activity) photoToLoad.imageView.getContext();
a.runOnUiThread(bd);
} catch (Throwable th) {
th.printStackTrace();
}
}
}
boolean imageViewReused(PhotoToLoad photoToLoad) {
String tag = imageViews.get(photoToLoad.imageView);
if (tag == null || !tag.equals(photoToLoad.url))
return true;
return false;
}
// Used to display bitmap in the UI thread
class BitmapDisplayer implements Runnable {
Bitmap bitmap;
PhotoToLoad photoToLoad;
public BitmapDisplayer(Bitmap b, PhotoToLoad p) {
bitmap = b;
photoToLoad = p;
}
public void run() {
if (imageViewReused(photoToLoad))
return;
if (bitmap != null)
photoToLoad.imageView.setImageBitmap(bitmap);
else
photoToLoad.imageView.setImageResource(stub_id);
}
}
public void clearCache() {
memoryCache.clear();
fileCache.clear();
}
}
This is a also my BaseAdapter.java class
public class BRIgeAdapter extends BaseAdapter {
private LayoutInflater inflater;
private Activity activity;
public ArrayList<HashMap<String, String>> data;
public ViewHolder holder;
public ImageLoader imageLoader;
HashMap<String, String> itemList;
private int screenSize;
MainActivity main;
public BRIgeAdapter(Activity a, ArrayList<HashMap<String, String>> d,int screenSize) {
this.activity = a;
this.data = d;
this.screenSize = screenSize;
inflater = (LayoutInflater) activity
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
imageLoader = new ImageLoader(activity.getApplicationContext());
}
public int getCount() {
return data.size();
}
public Object getItem(int position) {
return data.get(position);
}
public long getItemId(int position) {
return (long) position;
}
#Override
public int getViewTypeCount() {
return data.size();
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
holder = new ViewHolder();
main = new MainActivity();
convertView = inflater.inflate(R.layout.list_row, parent, false);
holder.journal = (TextView) convertView
.findViewById(R.id.smalljournal);
holder.statId = (TextView) convertView
.findViewById(R.id.smallstatID);
holder.smallDescription1 = (TextView) convertView
.findViewById(R.id.smallDescription1);
holder.DateTime = (TextView) convertView
.findViewById(R.id.smallDateTime);
holder.thumb_image = (ImageView) convertView
.findViewById(R.id.smallthumb);
holder.title = (TextView) convertView.findViewById(R.id.smalltitle);
holder.description = (TextView) convertView
.findViewById(R.id.smallDescription);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
itemList = data.get(position);
if (itemList != null) {
holder.journal.setText(itemList.get(MainActivity.KEY_journal));
// holder.DateTime.setText(itemList.get(MainActivity.KEY_pubDate));
holder.statId.setText(itemList.get(MainActivity.KEY_statID));
holder.smallDescription1.setText(itemList.get(MainActivity.KEY_description));
holder.journal.setTypeface(MainActivity.tf2);
String titleString = itemList.get(MainActivity.KEY_title);
Calendar cal = new GregorianCalendar(2013, 11, 20);
DateFormat df = new SimpleDateFormat("dd.MM.yyyy");
// DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
String date = df.format(cal.getTime());
String DateTime = itemList.get(MainActivity.KEY_pubDate);
DateTime = date;
holder.DateTime.setText(DateTime);
holder.title.setText(titleString);
holder.title.setTypeface(MainActivity.tf2);
holder.title.setLineSpacing(2, 1.2f);
holder.description.setLineSpacing(2, 1.2f);
if(screenSize == Configuration.SCREENLAYOUT_SIZE_NORMAL)
holder.description.setVisibility(View.INVISIBLE);
else
holder.description.setText(itemList.get(MainActivity.KEY_description));
holder.description.setTypeface(MainActivity.tf2);
imageLoader.DisplayImage(itemList.get(MainActivity.KEY_image),
holder.thumb_image);
}
return convertView;
}
static class ViewHolder {
public TextView journal, title, description,smallDescription1, DateTime, statId;
ImageView thumb_image;
}
}
Is there any possible way I can reduce or remove this lagging?

If you are using xml then set the width and height of the ListView to match_parent.

I see that you use Threads to load images from url. I Recommend you to use Android Universal Image Loader Library. It is pretty flexible and less laggy. You can find the whole information Here

Also, it looks like you are creating objects in the getView method. This means that when each view is drawn the OS must go through all the work creating those objects for you. If are working with a large list (or small amt of ram) you will force the garbage collector to run, causing stuttering of your app. Try to move all the object creation to the constructor method so it will only run once. Then just reassign them as needed in your get view method.
This should provide a noticable speed improvement.
Good luck ;)

how to parse and display a url contents inside a json array?

i have a images inside a jsonarray but like "flag": [
"http://www.simplydecoded.com/wp-content/uploads/2013/02/Telangana2.jpg"
]
but not displaying..
i am using this tutorial for parsing the data
and i sucessfully parsed all data but except images are not coming
i am using this to call images which are in side a json array actually its a url..
JSONArray json_query_flag = c.getJSONArray("flag");
and i followd remaning all fro this question..
it just extention of that not duplicate..
and i am using below for the part for the part of downloading image to bitmap
public class ImageLoader {
MemoryCache memoryCache = new MemoryCache();
FileCache fileCache;
private Map<ImageView, String> imageViews = Collections
.synchronizedMap(new WeakHashMap<ImageView, String>());
ExecutorService executorService;
// Handler to display images in UI thread
Handler handler = new Handler();
public ImageLoader(Context context) {
fileCache = new FileCache(context);
executorService = Executors.newFixedThreadPool(5);
}
final int stub_id = R.drawable.temp;
public void DisplayImage(String url, ImageView imageView) {
imageViews.put(imageView, url);
Bitmap bitmap = memoryCache.get(url);
if (bitmap != null)
imageView.setImageBitmap(bitmap);
else {
queuePhoto(url, imageView);
imageView.setImageResource(stub_id);
}
}
private void queuePhoto(String url, ImageView imageView) {
PhotoToLoad p = new PhotoToLoad(url, imageView);
executorService.submit(new PhotosLoader(p));
}
private Bitmap getBitmap(String url) {
File f = fileCache.getFile(url);
Bitmap b = decodeFile(f);
if (b != null)
return b;
// Download Images from the Internet
try {
Bitmap bitmap = null;
URL imageUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection) imageUrl
.openConnection();
conn.setConnectTimeout(30000);
conn.setReadTimeout(30000);
conn.setInstanceFollowRedirects(true);
InputStream is = conn.getInputStream();
OutputStream os = new FileOutputStream(f);
Utils.CopyStream(is, os);
os.close();
conn.disconnect();
bitmap = decodeFile(f);
return bitmap;
} catch (Throwable ex) {
ex.printStackTrace();
if (ex instanceof OutOfMemoryError)
memoryCache.clear();
return null;
}
}
// Decodes image and scales it to reduce memory consumption
private Bitmap decodeFile(File f) {
try {
// Decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
FileInputStream stream1 = new FileInputStream(f);
BitmapFactory.decodeStream(stream1, null, o);
stream1.close();
// Find the correct scale value. It should be the power of 2.
// Recommended Size 512
final int REQUIRED_SIZE = 70;
int width_tmp = o.outWidth, height_tmp = o.outHeight;
int scale = 2;
while (true) {
if (width_tmp / 2 < REQUIRED_SIZE
|| height_tmp / 2 < REQUIRED_SIZE)
break;
width_tmp /= 4;
height_tmp /= 4;
scale *= 4;
}
// Decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
FileInputStream stream2 = new FileInputStream(f);
Bitmap bitmap = BitmapFactory.decodeStream(stream2, null, o2);
stream2.close();
return bitmap;
} catch (FileNotFoundException e) {
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
// Task for the queue
private class PhotoToLoad {
public String url;
public ImageView imageView;
public PhotoToLoad(String u, ImageView i) {
url = u;
imageView = i;
}
}
class PhotosLoader implements Runnable {
PhotoToLoad photoToLoad;
PhotosLoader(PhotoToLoad photoToLoad) {
this.photoToLoad = photoToLoad;
}
#Override
public void run() {
try {
if (imageViewReused(photoToLoad))
return;
Bitmap bmp = getBitmap(photoToLoad.url);
memoryCache.put(photoToLoad.url, bmp);
if (imageViewReused(photoToLoad))
return;
BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad);
handler.post(bd);
} catch (Throwable th) {
th.printStackTrace();
}
}
}
boolean imageViewReused(PhotoToLoad photoToLoad) {
String tag = imageViews.get(photoToLoad.imageView);
if (tag == null || !tag.equals(photoToLoad.url))
return true;
return false;
}
// Used to display bitmap in the UI thread
class BitmapDisplayer implements Runnable {
Bitmap bitmap;
PhotoToLoad photoToLoad;
public BitmapDisplayer(Bitmap b, PhotoToLoad p) {
bitmap = b;
photoToLoad = p;
}
public void run() {
if (imageViewReused(photoToLoad))
return;
if (bitmap != null)
photoToLoad.imageView.setImageBitmap(bitmap);
else
photoToLoad.imageView.setImageResource(stub_id);
}
}
public void clearCache() {
memoryCache.clear();
fileCache.clear();
}
}

Try this..
JSONArray json_query_flag = c.getJSONArray("flag");
for(int i=0;i<json_query_flag.length();i++)
{
Log.v("URL"+json_query_flag.getString(i));
}
EDIT
ImageLoader imageLoader=new ImageLoader(activity.this);
and set image as
imageLoader.DisplayImage(URL, imageview);
here imageview is name of that imageview and URl is that string Url
OR
Bitmap bitmap = null;
try {
imageURL = new URL(utl2);
}
catch (MalformedURLException e) {
e.printStackTrace();
}
try {
HttpURLConnection connection = (HttpURLConnection) imageURL
.openConnection();
connection.setDoInput(true);
connection.connect();
InputStream inputStream = connection.getInputStream();
bitmap = BitmapFactory.decodeStream(inputStream);
image_view.setImageBitmap(bitmap);
} catch (IOException e) {
e.printStackTrace();
}